login script with dynamic output

We are accepting bids for a script that determines whether a user is logged in or not, and displays appropriate XHTML. The response should be contained in a &quot;login box&quot; (i.e. an HTML table element or CSS div element) that is the same size for both cases. If no user is logged in, the script should display a login/pass prompt as well as links to a &quot;password reminder&quot; page and a &quot;why join?&quot; page. If the user is logged in already, the response should be of the form &quot;Welcome $User&quot; with links to &quot;User Preferences&quot; &quot;Saved Searches&quot; and &quot;Watched Properties&quot;.

This script may be based off of our existing login form (which does simple logins only, with no dynamic response), or it may be entirely new code. The script should be written in PHP and interface to an existing MySQL database. We would prefer to not require the use of cookies from our users, although we are somewhat flexible in this regard.

The script should be secure from session hijacking and password sniffing and other false login techniques.

The code of the script myst be either the original creation of the programmer (must sign a statement granting all rights to use/modify/distribute the script to our company and a guarantee that no one else may lay claim to or revoke these rights) or licensed under BSD or GPL licensing terms.

More work may be requested if we are satisfied with the work on this project.